Presently there are methods of conversion with supply of electric energy. A representative method is the Huls process which makes possible the conversion of hydrocarbons such as methane into unsaturated hydrocarbons and in particular into acetylene. This process consists in passing methane into an electric arc and then in separating the products obtained. This process however has the inconvenience of generating a very substantial amount of carbon black.
Therefore an improvement has been proposed by using a hydrogen plasma. The hydrogen plasma allows to supply the energy required by the methane conversion reaction which is an endothermal reaction. This energy is supplied in situ by the plasma-producing gases without the agency of a wall. While plasma however is a source of power in the methane conversion reaction it still exhibits inconveniences since its temperature is too high for the reaction contemplated. Indeed methane brought to a temperature above 1,200.degree. C. would break down through a sequence of reactions of dehydrogenations and cyclizations into a mixture of polyaromatic substances leading to carbon black.
These methods therefore are not fully satisfactory since they involve an excessive build up of carbon black of uncontrolled quality which therefore becomes a by-product difficult to valorize.